The present invention relates to a living thing nurturing device, in particular, a device for effectively nurturing plants such as vegetables or the like which absorbs carbon dioxide and produces oxygen and funguses such as mushroom or fish which absorbs oxygen and produces carbon dioxide by profitably utilizing oxygen and carbon dioxide produced by the living things as mentioned above.
The present applicant has previously proposed various types of living thing nurturing devices for nurturing plants absorbing carbon dioxide CO.sub.2 and producing oxygen O.sub.2 and animals such as fish absorbing oxygen O.sub.2 and producing carbon dioxide CO.sub.2, in which plants and animals profitably exist together. Oxygen O.sub.2 produced by the plants is supplied to the fish while carbon dioxide CO.sub.2 produced by the fish is supplied to the plants with the intension of coexistence thereof.
On that occasion, for instance, in the case of cultivating vegetables such as tomatoes or the like as the aforementioned plants, usually, the vegetables can be most effectively nurtured at an approximate temperature of 20.degree. C. and a relative humidity of appoximately less than 60%. For this reason, the plants are cultivated in an air-tight receptacle, in which environment factors such as temperature, relative humidity, and the content rate of carbon dioxide CO.sub.2 is controlled at an optimum value for raising the plants. However, environment factors in air-tight receptacle change in accordance with the temperature and the humidity, etc. of the carbon dioxide CO.sub.2 supplied thereto, and therefore it is very difficult to control environment factors in an air-tight receptacle.